Process for oxidizing alkyl aluminum halides in presence of potassium salt



United States Patent O 3 262 957 PROCESS FOR OXIDIZING ALKYL ALUMINUM HALIDES IN PRESEN CE OF'POTASSIUM SALT Max 1E. Roha, 8205 Parkview Road, andWarren L. Beears, 9307 Glenwood Trail, both of Brecksville, Ohio No Drawing. Filed Apr. 18, 1960, Ser. No. 22,702 5 Claims. (Cl. 260-448) This invention relates to a process for the oxidation of alkyl aluminum halides, and particularly to a process for the oxidation of mixed telomer alkyl aluminum halides, which constitutes an essential step in the production of telomer alcohols directly from ethylene, or other alphaolefins, by a process in which hydrocarbon groups are inserted into mixed alkyl aluminum halides, such as an alkyl aluminum sesquichloride, by chain growth, that is telomerization, to produce mixed telomer alkyl aluminum halides, the mixed telomer alkyl aluminum halides being oxidized to produce oxidized mixed alkyl aluminum halides, and the oxidized mixed alkyl aluminum halides being hydrolyzed to produce mixed telomer alcohols having the same number of carbon atoms as the mixed telomer alkyl aluminum halides.

In the above indicated prior process for the production of telomer alcohols, the resulting telomer alcohols contain a considerable proportion, as from 12 to 20%, of free hydrocarbons, having hydrocarbon chains of substantially the same chain length as the hydrocarbon chains of the telomer alcohols and boiling points within substantially the same range as those of the telomer alcohols, and hence these free hydrocarbons cannot be economically separated out from the telomer alcohols by fractional distillation or other practical means.

Applicants have by extensive experimentation and tests determined that the presence of these free hydrocarbons, that cannot be separated out by practical means, is largely due to side reactions during the oxidation step, which by detachment of the aluminum atoms from the telemerized alkyl groups of the telomerized mixed alkyl aluminum halides produce, as unwanted by-products, free hydrocarbons of such a chain length that the free hydrocarbons so produced have approximately the same boiling points as the telomerized alcohols and hence are not commercially separable from the latter.

An object of this invention is to provide a new and improved process, which is preferably carried out at substantially atmospheric pressure, for the oxidation of alkyl aluminum halides, and particularly for the oxidation of mixed telomer alkyl aluminum halides obtained by the insertion of hydrocarbon groups into mixed alkyl aluminum halides by chain growth, the mixed telomer alkyl aluminum halides of this invention having the general formula (C H AlHa in which n is an integer ranging from 6 to 30, Ha is a halogen, and x and y are numerical values ranging from 2.7 to 0.3 and whose sum is 3, which oxidation process produces oxidized mixed telomer alkyl aluminum halides in high yield and with a minimum of by-product free hydrocarbons having boiling points which are within the range of the boiling points of the telomer alcohols produced therefrom.

In order to make clear the part which the present invention takes in the manufacture of telomer alcohols, and utilizing ethyl aluminum sesquichlorides as the starting mixed alkyl aluminum halides, ethylene as the alphaolefin, and assuming the values of x and y each average 1.5, the manufacture of the telomer alcohols may be illustrated by the following series of equations which represent the main reactions:

wherein 111 represents a number of moles of ethylene required for the reaction, it represents the average number of carbon atoms in the telomerized alkyl chains, which, for detergents, normally ranges from 6 to 16 carbon atoms and for other industrial uses ranges from 16 to 30 carbon atoms, and each of the formulas, after which the asterisks occur, the 1.5 value represents the average values of x and y of the mixed reaction products, the values of x and y may vary as widely as from 2.7 to 0.3 and are commonly of the order of 1.8 to 1.2.

It is to Step 3 above, namely, the oxidation step, that the invention of this application primarily relates.

Applicants have discovered by extensive experimentation and tests that telomer alkyl aluminum halides of the general formula (C H AlHa are capable of producing telomer alcohols up to 97%+ purity, and even to 99.9% purity, by the anhydrous reaction resulting from the addition before oxidation, of a specific blocking complex consisting of an anhydrous dispersion or slurry of certain anhydrous potassium salts to the mixed telomer alkyl aluminum halides, in an inert dry atmosphere, as under a blanket of dry nitrogen, and that where the oxidation step is so carried out, the resulting oxidized mixed telomer alkyl aluminum halides are substantially free of hydrocarbon impurities, that is, they contain from 0.1% to 3% of free hydrocarbons.

The liquid organic anhydrous dispersant employed in this invention may be any of the well known anhydrous organic liquids, such as pentane, hexane, heptane, octane and the like, or mixtures of alkanes, such as Deobase kerosene, or mixtures resulting from the Fischer- Tropsch process, or a cycloalkane, such as cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane and the like, or a benzene hydrocarbon, such as benzene, toluene, xylene and the like, or tetrahydrofuran, isopropyl ether, and the like, or mixtures of any of them. The anhydrous potassium salts include the chloride, bromide, iodide, fluoride, acetate, tetraborate, phosphate, and carbonate. The potassium salt in finely divided particles is intimately dispersed in the liquid organic anhydrous dispersant, or mixtures thereof, to secure a uniform dispersion or slurry of the potassium salt in the anhydrous liquid dispersant. .The anhydrous dispersion of the potassium salt is added to the anhydrous mixed telomerized alkyl aluminum halides, which may have been previously dispersed in an anhydrous liquid organic dispersant of the type hereinabove in this paragraph enumerated.

A catalyst of oxidation is not essential and is not generally employed. Where desired, the chlorides of the transition elements, such as titanium, zirconium, hafnium, thorium, vanadium, may be satisfactorily employed. The oxidation step is preferably carried out by bubbling dry oxygen gas through the admixture of the above indicated constituents under a blanket of a dry inert gas, as dry nitrogen.

It is to be understood that the invention of this application is not limited to any particular apparatus for the carrying out of the process of this invention. A suitable oxidation reactor comprises a fluidtight reaction vessel equipped with stirrer, thermometer, inlet and outlet connections, including an inlet for purging with dry inert gas and an inlet for delivering oxygen, preferably in measured amounts, as through a dry gas meter, from a source of oxygen supply and preferably into the bottom of the reactor, and a reflux condenser through which gases, such as the purging dry inert gases and unreacted oxygen may be vented from the upper portion of the reactor, whereas the vapors of the solvent are condensed and the condensate returned to the reactor. It is also desirable to place in the outlet of the reflux condenser a gas meter to measure the amount of non-condensed gases discharged from the reflux condenser. There is also provided means for removing from the reactor contents the exothermal heat generated by the oxidation reaction, such as an outside cooling jacket or inside cooling coils, or both, and, if desired, for maintaining a substantially constant temperature, although the temperature of oxidation is not critical. In addition, there is normally provided a supply means for delivering the telomer alkyl aluminum halides in measured amounts into the reactor, and storage means for the dispersion of the potassium salt and dispersant, with means for delivering from the storage means to the reactor measured amounts of the anhydrous dispersion of the potassium salt, as well as means for removing from the reactor the contents thereof after the oxidation has been completed.

GENERAL EXAMPLE In carrying out the process of oxidizing anhydrous telomer mixed alkyl aluminum halides, an oxidation reactor of a type hereinabove described is thoroughly purged of all air and moisture. A measured amount of anhydrous telomer mixed alkyl aluminum halides, which may be dispersed in an anhydrous organic liquid dispersant, is charged into the purged reactor and the stirrer placed in operation. Then, a measured amount of finely divided anhydrous potassium salt dispersed in an anhydrous organic liquid dispersant is fed into the reactor, and thoroughly admixed with the telomer mixed alkyl aluminum halides. Thereafter, dry oxygen is fed into the bottom of the reactor and bubbled up through the agitating liquid contents of the reactor, and the means for removing the exothermally generated heat of oxidation is placed in operation. The temperature of the reactor contents during oxidation is not critical, the oxidation reaction taking place over a wide range of temperatures, as from 40 C. to 100 C., or higher, the upper limit however should not be much higher, as not over C. higher, than the boiling points of any of the organic liquids in the reactor, since economy in operation requires that the organic liquid dispersant be returned from the reflux condenser to the reactor. Experience has shown that for best results the temperature should be controlled between 10 C. and 100 C.

When the oxidation reaction is completed, that is, no more oxygen is being taken up, as indicated by the inlet oxygen meter and the outlet meter of the reflux condenser, the flow of oxygen is cut off. Thereupon, the potassium salt is removed from the reactor contents by centrifugation, as by a Baker-Perkins centrifuge, or, alternatively, by filtration, as by an Oliver continuous rotary drum filter, then the liquid organic dispersants are distilled from the reactor contents, and finally the free hydrocarbons are stripped from the remainder of the reactor contents by a high vacuum film stripper, such as a Kontro stripper. There results oxidized telomer alkyl aluminum halides, having only a very low percentage of free hydrocarbons, which may be then hydrolyzed with a liquid proton donator, of which water alone is preferred, to yield telomer alcohols of high purity having from 0.1% to 3% free hydrocarbons.

Alternatively, the entire contents of the oxidation reactor, after oxidation is completed, may be treated with a liquid proton donator, such as water, to produce telomer alcohols. Then, the reactor contents are separated into two portions, a heavier aqueous portion containing the potassium salt and a lighter liquid organic portion containing the higher alcohols. This separation may be carried out by settling, that is allowing the reactor contents to stand, as in a separation funnel, or by centrifugation. From the lighter organic portion are recovered by distillation higher alcohols having from 0.1% to 3% free hydrocarbons.

Example I The following, which is illustrative of the one embodiment of the process of this invention, demonstrates the effective oxidation of n-octyl aluminum sesquichloride.

Utilizing the procedure outlined in the general example, 58.7 g. (0.234 mole) of anhydrous n-octyl aluminum sesquichloride, or mixed n-octyl aluminum chlorides, are charged into the purged oxidation reactor above described, and, while vigorously stirring, 17.3 g. (0.234 mole) of finely divided anhydrous potassium chloride, uniformly dispersed in 62.5 g. of dry tetrahydrofuran, are charged into the reactor and thoroughly admixed with the n-octyl aluminum sesquichloride. While vigorously stirring, bubble oxygen slowly through the reactor contents and by means of the cooling mechanism preferably maintain the temperature of the reactor contents below about C. (the boiling point of tetrahydrofuran is 66 C.), until no further oxygen is taken up by the reactor contents. To the resulting oxidized n-octyl aluminum sesquichloride is added, with stirring, ml. of water, and the mixture is allowed to stand, whereupon it separates into two liquid layers, a lower water layer in which the KCl is dispersed, and an upper liquid organic (tetrahydrofuran) layer in which the alcohol is dissolved. The upper organic liquid layer is separated from the lower water layer, washed two times with distilled water, then two times with an acid sodium carbonate solution, and finally four times with distilled water, to produce a neutral organic liquid layer, from which the tetrahydrofuran is removed by vacuum distillation, leaving n-octyl alcohol (32.3 g.) which analysis shows to be a 98.2% pure n-octyl alcohol.

Example II Illustrative of another embodiment of this invention, which utilizes the starting constituents of Example I, charge into the purged reactor 58.7 g. (0.234 mole) of anhydrous n-octyl aluminum sesquichloride dispersed in 200 g. of hexane and 17.3 g. (0.234 mole) of finely divided anhydrous potassium chloride, uniformly dispersed in 62.5 g. of dry tetrahydrofuran, and thoroughly admix. While vigorously stirring, bubble oxygen slowly into the reactor contents, preferably maintaining the temperature of the reactor contents below about 75 C. to prevent undue loss of hexane and tetrahydrofuran, until no more oxygen is taken up. The reactor contents are filtered or centrifuged to remove the potassium chloride, and the hexane and tetrahydrofuran are removed by vacuum distillation, after which the oxidized n-octyl aluminum sesquichloride is stripped of free hydrocarbons by a high vacuum (0.05 mm.) film stripper at 200 C. The stripped oxidized n-octyl aluminum sesquichloride is then hydrolyzed, by adding thereto a proton donating compound, as 160 ml. of water, and the resulting mixture allowed to stand, and, as previously described, it separates into two liquid layers, a lower water layer and an upper organic liquid layer, which on washing, neutralizing and distillation yields an n-octyl alcohol which on analysis is shown to be 99.6% pure n-octyl alcohol.

Example Ill Utilizing the procedure of the general example and the specific method of Example II, but starting with mixed telomer alkyl aluminum sesquichlorides of the formula (C l-I AlC1 wherein the average value of n is 14, 416 g. of the mixed telomer alkyl aluminum sesquichloride are charged into the purged oxidation reactor, and, while vigorously stirring, a uniform dispersion of 26.9 g. of anhydrous potassium chloride in 141 g. of dry tetrahydrofuran is charged into the reactor and the reactor contents thoroughly intermixed. While continuing the stirring, oxygen is bubbled slowly into the reactor contents, preferably maintaining the temperature of the reactor contents from 20 C. to 70 C., until no more oxygen is taken up, as is indicated by the inlet oxygen and outlet gas meters. The potassium chloride is removed by cen' trifuging or by filtration. The tetrahydrofuran is removed from the reactor contents by vacuum distillation, after which the oxidized mixed telomer alkyl aluminum sesquichlorides are stripped of free hydrocarbons by a high vacuum (0.05 mm.) film stripper at 200 C. The oxidized mixed telomer alkyl aluminum sesquichlorides, stripped of free hydrocarbons, are then hydrolyzed, and the telomer alcohols isolated and analyzed for free hydrocarbons with the following result:

TABLE I [Percent Free Hydrocarbon Content In Alcohols Isolated] Example IV Utilizing the process of the general example, a dispersion containing 1200 g. of heptane and 416 g. of mixed telomer alkyl aluminum sesquichlorides of the formula (C H AlCl wherein n, the average carbon chain length, is 14 and x and y range in numerical values from 0.8 to 2.2, are charged into the purged oxidation reactor, and, while vigorously stirring, a uniform dispersion of 26.9 g. of anhydrous potassium chloride in 141.5 g. of dry heptane is charged into the reactor. While vigorously stirring, bubble oxygen through the reactor contents and by means of the cooling mechanism preferably maintain the temperature below about 105 C. (boiling point of heptane is 98 C.) until no further oxygen is taken up by the reactor contents. The potassium chloride is removed by centrifuging or by filtration. The heptane is removed from the reactor contents by vacuum distillation, after which the oxidized mixed telomer alkyl aluminum sesquichlorides which are stripped of free hydrocarbons by a high vacuum (0.05 mm.) film stripper, as a Kontro stripper, at 250 C. The resulting oxidized mixed telomer alkyl aluminum sesquichlorides, stripped of free hydrocarbons, are treated with a weak hydrolyzing acid, such as sulfuric acid, to produce the telomer alcohols, which are separated out from the reactor contents and then fractionally distilled under vacuum to yield the following alcohols:

TABLE II Telomer Alcohol (TA) Percent HO Percent Purity of TA (1) Decyl alcohol 1 99. 9 (2) Dodccyl alcohol .1 99.9 (3) Tetradecyl alcoho .2 99. 8 (4) Hexadccyl alcohol 6 99. 4

TAB LE III Telomer Alcohol (TA) Percent Hydro- Icrcent Purity carbon of TA (1) Octadecyl alcohol 1.4 98.6 (2) Eicosyl alcohol 1. 6 98.4 (3) Docosyl alcohol 1. 6 98. 4 (4) Tctracosyl alcohol. 1. 8 98. 2 (5) Octacosyl alcohol 1.8 98.2 (6) Triacontyl alcohol 2.0 98.0

In carrying out the reactions of the general example to produce telomer alcohols, the proportions of the anhydrous potassium salt to the telomer alkyl aluminum sesquihalides are not critical and may vary widely. Tests have shown that 0.125 mole of the potassium salt to one mole of the aluminum present in the telomer alkyl aluminum sesquihalides give excellent results and that higher ratios may also be used. An excess of the potassium salt, as 2.5 moles of the potassium salt to one mole of aluminum, gives excellent results.

The amount of the organic liquid is also not critical. Generally, one part by volume of the potassium salt to from 0.5 to 10 parts of the anhydrous organic liquid gives excellent results, although higher percentages of organic liquid have been found to give equally satisfactory results, and to be desirable where the potassium salt does not readily disperse in the organic liquid. Again, where 10 volumes of organic liquid to one volume of the telomer alkyl aluminum halides are employed, telomer alcohols of high yield are obtained by the process of this application.

Examples V to X Repeating the procedure of Example II, with only changes in the proportions of the potassium salt, the noctyl aluminum sesquichlorides and the tetrahydrofuran solvent, as indicated in Table IV below, the results therein noted were attained.

TABLE IV Ratio, Ratio, Organic Yield Percent Example No. KCl/Al Liquid/Telomer Of Oxidized Telomer The non-critical character of the proportions of anhydrous potassium salt, telomer alkyl aluminum halides and organic liquid is demonstrated in the above table.

dation was carried out at different temperatures with the following results:

TABLE V Alkaline Oxidation Telomer Example Metal Salt KIAI Temp., 0. Alcohol Purity In Example XII, the temperature was slowly increased during the run. These Examples XI to XIII demonstrate that the temperature of oxidation is not critical in the process of this invention.

7 Examples XIV to XXV Tests to date indicate that potassium chloride and tetrahydrofuran are somewhat more effective than other combinations of a potassium salt and an organic liquid, making up the blocking complex. However, the other anhydrous potassium salts and organic liquids produce effective blocking complexes in the oxidation process of Example II, as is indicated in the Examples XIV to XXV, the results of which are indicated in the following table, in which the abbreviation THF represents tetrahydrofuran; PEN, pentane; HEX, hexane; HEP, heptane; IPE, isopropyl ether; KAC, potassium acetate; the other salts being represented 'by their accepted chemical formulas:

TABLE VI Example Solvent Percent Free Hydrocarbons Further tests demonstrate that similar results to those indicated in Table VI above are obtained where the anhydrous organic liquid is a mixture of alkanes, such as Deobase kerosene and Fischer-Tropsch alkanes; a cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, benzene, toluene, zylene, and the like.

While the invention of the application has been illustrated by a limited number of specific examples, it is to be understood that the said invention is not restricted thereto, that modifications in the proportions and types of materials employed may be varied, and that equivalent materials, as defined in the specification, may be employed where desirable, without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. The process for forming oxidation products of mixed alkyl aluminum halides, said oxidation products being suitable for hydrolysis to form high purity telomer alcohols, which process consists of adding dry oxygen gas to an aqueous dispersion containing (1) mixed alkyl aluminum halides, (2) an anhydrous liquid diluent and (3) a finely divided potassium salt until uptake of oxygen gas is essentially complete, whereby the presence of said potassium salt substantially prevents the occurrence of side reactions producing hydrocarbon impurities in the resulting oxidation products; said mixed alkyl aluminum halides being of the empirical formula in which n is an integer from 6 to 30, Ha is halogen and x and y are numerical values ranging from 2.7 to 0.3 and whose sum is 3, and said potassium salt being selected from the class consisting of the chloride, bromide, iodide, fluoride, acetate, tetraborate, phosphate and carbonate of potassium.

2. The process of claim 1 in which the anhydrous liquid diluent is selected from the class consisting of pentane, hexane, heptane, octane, cyclopentane, cyclohexane, methyl cyclopentane, methyl cyclohexane, benzene, toluene, xylene, tetrahydrofuran, isopropyl ether and mixtures thereof, in anhydrous form.

3. The process of claim 2 in which the halide is chlorine.

4. The process of claim 3 in which the potassium salt is potassium chloride.

5. The process of claim 4 in which the anhydrous liquid diluent is anhydrous tetrahydrofuran.

References Cited by the Examiner UNITED STATES PATENTS 2,892,858 6/1959 Ziegler 260632 X 3,016,397 1/1962 Walde 260448 FOREIGN PATENTS 808,055 1/1959 Great Britain.

TOBIAS E. LEVOW, Primary Examiner.

LEON ZITVER, Examiner.

J. ZIEGLER, A. H. SUTTO, Assistant Examiners. 

1. THE PROCESS FOR FORMING OXIDATION PRODUCTS OF MIXED ALKYL ALUMINUM HALIDES, SAID OXIDATION PRODUCTS BEING SUITABLE FOR HYDROLUYSIS TO FORM HIGH PURITY TELOMER ALCOHOLS, WHICH PROCESS CONSISTS OF ADDING DRY OXYGEN GAS TO AN AQUEOUS DISPERSION CONTAINING (1) MIXED ALKYL ALUMINUM HALIDES, (2) AN ANHYDROUS LIQUID DILUENT AND (3) A FINELY DIVIDED POTASSIUM SALT UNTIL UPTAKE OF OXYGEN GAS IS ESSENTIALLY COMPLETE, WHEREBY THE PRESENCE OF SAID POTASSIUM SALT SUBSTANTIALLY PREVENTS THE OCCURRENCE OF SIDE REACTIONS PRODUCING HYDROCARBON IMPURITIES IN THE RESULTING OXIDATION PRODUCTS; SAID MIXED ALKYL ALUMINUM HALIDES BEING OF THE EMPIRICAL FORMULA 